Please smile?

How can a toddler be so frustrating and so adorable at the same time? I'm not sure, but somehow Haley manages it with no effort at all. Her latest tactic to drive us to insanity is this:

Haley will refuse to cooperate in accomplishing any task, such as getting dressed, brushing teeth, brushing hair, getting shoes on, etc. By not cooperating, I mean she will not sit still and will run off at any given opportunity, in search of entertainment. When I have reached my absolute limit of patience, she will return docilely and cooperate, looking beguilingly in my eyes and beseech me, "Please smile" in her cutest little voice ever. If I do not immediately smile in return, she will continue to smile, asking "Please? Pretty please? Pretty pretty please?" And today she added a new one, "Please can you make a happy noise?" Somehow, she always manages to turn the situation to her advantage! How do you battle that tactic?